Question Will all motherboards spin the fans at full power for a second at startup?

steve17

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Apr 17, 2010
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My old Intel boards did. My new ASRock Z590 Extreme WiFi doesn't. I have a 12cm slow turning Nexus 3 pin case fan. Sometimes it fails to start turning if I have the speed set too low.

I read that the momentary fast speed is also to blow the dust off heat sinks.
 

jay32267

Champion
I think some MBs do and some don't.
I think it would depend on the BIOS code....or perhaps they default to full speed until the BIOS takes over.
I've had motherboards that do it and motherboards that don't.
I'd replace the fan...the bearings sound like they're failing.
 

geofelt

Titan
I always thought it was to test that there was actually a cooler and fan installed.

As to a fan not starting, you need about 5v to get most fans started.
If your fan profile is set too low for 3 pin fans, they may not start.
 

Paperdoc

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I always understood that this is always done at the beginning of the POST process on any mobo, and the purpose is to ensure that the fan DOES start before being slowed down to whatever is required. However, I am NOT sure this is always done if you choose NOT to let the automatic system exercise control. IF you have chosen to run that fan at a fixed slow speed for noise reduction (also reduces cooling, of course), on some mobos it may NOT use that full-speed first start-up option. In those cases it is YOUR responsibility to arrange to ensure start-up.
 

steve17

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Thanks for the info guys.

I will be building 2 more computers in the next few years. I would feel better about them if the mobo kicked the fans in the azz to make sure they started spinning. Anybody know what brands do this?

I think Asus is a good brand. I'll probably go to their website and ask.
 

steve17

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I made no changes to this mobo fan control. I found a fan power port that ran the fan at around 700 RPM. I then used a fan cable with a resistor that slowed it to around 550 rpm. When I saw the fan fail to start once, I changed the fan cable so it runs at around 650 rpm and I've not seen it fail to start since.

These fans are fairly quiet at most speeds. I'm not a gamer, I just like cool quiet computers. The faster the fans run, the quicker they wear out, although these fans usually last over ten years. The faster the case fans run, the more air they pull in, and the quicker the air filters load up with dust.
 

avg9956

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Apr 7, 2019
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I always thought that the BIOS is late at loading the fan settings hence, why the fan spins at max RPM from cold booting.
Since BIOS is based on per mobo manufacturer, then maybe some mobo manufacturers have figured out a way to instantly load fan settings.

The faster the fans run, the quicker they wear out, although these fans usually last over ten years.
True
It depends on the bearing of the fan.

and the quicker the air filters load up with dust.
Shouldn't be too much of a concern if you clean the filters every 1-2 months.
 

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